Singly_Linked_List.c

#include<stdio.h>
#include<stdlib.h>
struct node
{
    int data;
    struct node *next;
};
struct node *head=NULL,*newnode,*temp;
void create()
{
    head=NULL;
    newnode=(struct node *)malloc(sizeof(struct node));
    printf("Enter data : ");
    scanf("%d",&newnode->data);
    newnode->next=NULL;
    head=newnode;
}
void insert_beg()
{
    newnode=(struct node*)malloc(sizeof(struct node));
    printf("Enter data : ");
    scanf("%d",&newnode->data);
    newnode->next=NULL;
    if(head==NULL)
    {
        head=newnode;
    }
    else
    {
        newnode->next=head;
        head=newnode;
    }
}
void insert_any()
{
    int pos,i=1;
    printf("Enter the position : ");
    scanf("%d",&pos);
    if(pos==1)
    insert_beg();
    else
    {
        temp=head;
        while (i<pos-1)
        {
            temp=temp->next;
            i++;
        }
        newnode=(struct node*)malloc(sizeof(struct node));
        printf("Enter data : ");
        scanf("%d",&newnode->data);
        newnode->next=temp->next;
        temp->next=newnode;
    }
}
void insert_last()
{
    newnode=(struct node*)malloc(sizeof(struct node));
    printf("Enter data : ");
    scanf("%d",&newnode->data);
    newnode->next=NULL;
    if(head==NULL)
    {
        head=newnode;
    }
    else
    {
        temp=head;
        while (temp->next!=NULL)
        {
            temp=temp->next;
        }
        temp->next=newnode;
    }
    
}
void delete_beg()
{
    if(head==NULL)
    printf("Cannot delete !!! List is empty");
    else
    {
        temp=head;
        head=head->next;
        free(temp);
    }
    
}
void delete_any()
{
    if(head==NULL)
    printf("Cannot delete !!! List is empty\n");
    else
    {
        int pos,i=1;
        printf("Enter position : ");
        scanf("%d",&pos);
        temp=head;
        while(i<pos-1)
        {
            temp=temp->next;
            i++;
        }
        nextnode=temp->next;
        temp->next=nextnode->next;
        free(nextnode);
    }
}
void delete_last()
{
    if(head==NULL)
    printf("Cannot delete !!! List is empty");
    else
    {
        struct node *prevnode;
        temp=head;
        while(temp->next!=NULL)
        {
            prevnode=temp;
            temp=temp->next;
        }
        if(head==temp)
        head=NULL;
        else
        prevnode->next=NULL;
        free(temp);
    }
}
void display()
{
    int count=0;
    temp=head;
    printf("Elements are : ");
    while(temp!=NULL)
    {
        printf("%d ",temp->data);
        temp=temp->next;
        count++;
    }
    printf("\nTotal number of elements : %d\n",count);
}
int main()
{
    int op,ch;
    while(1)
    {
        printf("\n1. Create a list\n2. Insert an element\n3. Delete an element\n4. Display the elements\n5. Exit\n\nEnter your choice : ");
        scanf("%d",&op);
        switch (op)
        {
        case 1:
            create();
            break;
        case 2:
            {
            printf("\n1. Insert at beginning\n2. Insert at any position\n3. Insert at last\n\nEnter your choice : ");
            scanf("%d",&ch);
            switch (ch)
            {
            case 1:
                insert_beg();
                break;
            case 2:
                insert_any();
                break;
            case 3:
                insert_last();
                break;
            default:
                printf("Wrong choice !!! Try again..");
                break;
            }
            break;
            }
        case 3:
            {
            printf("\n1. Delete from beginning\n2. Delete from any position\n3. Delete from last.\n\nEnter your choice : ");
            scanf("%d",&ch);
            switch (ch)
            {
            case 1:
                delete_beg();
                break;
            case 2:
                delete_any();
                break;
            case 3:
                delete_last();
                break;
            default:
                printf("Wrong choice !!! Try again..");
                break;
            }
            break;
            }
        case 4:
            display();
            break;
        case 5:
            exit(0);
            break;
        default:
            printf("Wrong Choice!!\nTry again\n");
            break;
        }
    }
}